This invention relates generally to a rotating spinning ring assembly for spinning and twisting frames, and an improved air bearing arrangement therefor.
The advantage of utilizing freely rotatable spinning rings supported on an air bearing are well-known, such advantages including increased operating speeds and a significant reduction in wear caused by friction inherently present in conventional mechanical bearing assemblies for spinning ring frames. However, despite these advantages, difficulties have been encountered in designing an air bearing arrangement that achieves a properly balanced air flow within the air bearing that will permit a rapid and smooth lifting of the spinning ring when air is first introduced into the air bearing arrangement upon start-up of the operation of the frame, and that reduces undesirable coasting of the spinning ring after the yarn spindle drive is cut off so as to avoid yarn tangling and yarn breakage following such cut off.
Some efforts have been made to improve the air flow characteristics in the basic air bearing arrangement for spinning rings that is believed to be initially disclosed in Klutz U.S. Pat. No. 3,324,643, including a specially formed plenum or air chamber in the air bearing arrangement as disclosed in Baucom et al U.S. Pat. No. 4,270,340 and Chilpan U.S. Pat. No. 3,481,131. One specific feature of the Chilpan ring assembly is the utilization of baffles disposed at the exit ends of both of the radial air flow passageway extending from the point within the air bearing where pressurized air is introduced, these baffles at both air flow passageways being provided for the specific purpose of creating an equal air flow resistance for both passageways so that the air flow through such passageways is balanced or equalized as nearly as possible.
It has been found, however, that when the flow through both of the radial air flow passageways is substantially equalized, there is a significant loss of air flow through the radial passageway at the bottom of the ring, and, therefore, less of the pressurized air introduced into the air bearing is applied to lift the ring member off of the ring holder, particularly at start-up. Consequently, it is necessary in arrangements of the type to use a large air compressor, or other source of pressurized air, which significantly increases the initial costs and operating costs of the apparatus, and which makes it more difficult to stop the rotation of the ring member after the yarn spindle drive is cut off.
In an effort to over come the foregoing drawbacks of equalized air flow through the radial and axial air flow passageways, the above-identified commonly owned Baucom et al patent discloses an air bearing arrangement for a spinning ring in which the pressurized air is admitted into a relatively large, open annular plenum between the ring member and the ring holder, and the axial passageway extending therefrom has a tapered configuration so that the axial spacing increases gradually in the direction toward the radial spacing. While this arrangement is believed to be generally satisfactory in some applications, the uninterrupted flow of pressurized air from the bottom of radial passageways, particularly at start-up, nevertheless requires a relatively large capacity source of compressed air for proper operation of the apparatus in other applications.
In accordance with the present invention, an improved air bearing arrangement is provided which overcomes or alleviates the above-described drawbacks of known airborne spinning and twisting ring devices.